Progressive rock

Progressive rock bands went beyond the established rock music formulas by experimenting with different instruments, song types, and musical forms. The Who popularized the rock opera. Some bands such as Pink Floyd, The Moody Blues, Procol Harum, and Deep Purple experimented with new instruments including wind sections, string sections, and full orchestras. Many of these bands moved well beyond the formulaic three-minute rock songs into longer, increasingly sophisticated songs and chord structures. With inspiration from these earlier artists, referred to as "proto-prog", it flowered into its own genre, initially based in the UK, after King Crimson's 1969 genre-defining debut album, In the Court of the Crimson King. Progressive rock bands borrowed musical ideas from classical, jazz, electronic, and experimental music. Progressive rock songs ranged from lush, beautiful songs to atonal, dissonant, and complex songs. Few achieved major mainstream success, but large cults followed many of the groups. Pink Floyd, Yes, Rush, Jethro Tull, Genesis, and a few less notable others were able to work in hit singles to their otherwise complex and untraditional albums to garner a larger audience.